Ulcerative Colitis
A chronic relapsing inflammatory bowel disease limited to the colon and rectum.
Overview
Ulcerative colitis (UC) is a chronic immune-mediated inflammation of the colonic mucosa, extending continuously from the rectum. It causes bloody diarrhoea and abdominal pain with flares and remissions. Modern therapy aims for mucosal healing and reduces need for surgery.
Symptoms
- • Bloody diarrhoea, often with mucus
- • Urgency and tenesmus
- • Lower abdominal cramping
- • Fatigue, weight loss
- • Extra-intestinal: arthritis, uveitis, erythema nodosum, primary sclerosing cholangitis
Risk factors
- • Family history of inflammatory bowel disease
- • Age 15–30 (peak), second peak 50–70
- • Northern European or Ashkenazi Jewish ancestry
- • NSAID use can trigger flares
Causes
- • Dysregulated immune response to gut microbiota in genetically susceptible individuals
- • Smoking is protective (do NOT start smoking)
- • Appendicectomy in childhood may be protective
🚨 Red flags — seek urgent care
- • Severe flare: >6 bloody stools/day with fever, tachycardia or anaemia — urgent admission
- • Abdominal distension and pain — possible toxic megacolon, emergency
- • Persistent vomiting or signs of dehydration
When to seek care
- • Persistent bloody diarrhoea
- • Flare not responding to usual treatment
- • Any red flag symptom
Diagnosis
- • Stool tests to exclude infection (including C. difficile)
- • Faecal calprotectin (raised)
- • Colonoscopy with biopsies — continuous inflammation from rectum
- • Bloods: FBC, CRP, ferritin, vitamin D, liver tests
Treatment
- • Mild–moderate: oral and topical 5-ASA (mesalazine)
- • Moderate–severe flares: oral or IV corticosteroids (short course)
- • Immunomodulators (azathioprine), biologics (infliximab, vedolizumab, ustekinumab), JAK inhibitors (tofacitinib)
- • Colectomy for medically refractory disease, dysplasia or cancer
- • Vaccinations, bone protection and cancer surveillance
Prevention
- • No way to prevent UC
- • Avoid NSAIDs which can trigger flares
- • Maintenance therapy adherence prevents relapse
Complications
- • Toxic megacolon, perforation
- • Severe bleeding
- • Colorectal cancer (especially with >10 years pancolitis)
- • Primary sclerosing cholangitis
- • Anaemia, osteoporosis, growth failure in children
Prognosis
UC follows a relapsing-remitting course; about half need biologic therapy and around 10–15% eventually require colectomy. With modern care, most maintain good quality of life and life expectancy approaches normal.
Education & self-care
Ulcerative colitis is treatable and most people achieve sustained remission with the right therapy and monitoring.
Frequently asked questions
Is UC the same as Crohn's?
Both are inflammatory bowel diseases. UC affects only the colon and is continuous; Crohn's can affect any part of the gut and is patchy and transmural.
Will I need surgery?
About 10–15% of people with UC ultimately need colectomy. Modern biologics have substantially reduced surgery rates.
How is a flare treated?
Mild flares are usually treated with mesalazine. Moderate flares need oral steroids; severe flares require hospital admission for IV steroids and consideration of biologic rescue therapy.
Will I need surgery?
Around 15–20% of people with UC eventually need colectomy, usually for severe disease unresponsive to medication or for dysplasia. Restorative procedures (ileoanal pouch) preserve continence in most.
Is bowel cancer more common in UC?
Yes — risk rises with disease duration, extent and severity. Surveillance colonoscopy is recommended from 8–10 years after diagnosis, with intervals based on individual risk.